In some geographical areas, fluid produced from a well may yield crude oil having substantial quantities of water and undesired substances, such as salt. In some instances, the salt and water content may be so high as to interfere with subsequent transportation, storage, and refining of the crude. Salt and water in the crude may be highly deleterious to some metal equipment and piping, and therefore it may be desirable that at least some of the water and undesired substances salt be separated and removed from the crude.